“I’m not your buddy, Simpson,” Grimey told his co-worker. “I don’t like you. In fact, I HATE you! Stay the hell away from me, because from now on, we’re ENEMIES!”

Although Grimey was an extremely hard worker and a super intelligent guy, it was his obsession with despising Homer that caused his ultimate death in the Season 8 episode “Homer’s Enemy.” Grimey was in the middle of a psychotic break, impersonating Homer and running like a crazed man all over the nuclear plant. He grabbed “extremely high voltage” cables with his bare hands (because that’s what Homer would do), and he was electrocuted to death.

Well, good news for Grimey fans… he’s coming back to Springfield! And he definitely hasn’t forgotten about his hatred for Homer.

Voiced by Hank Azaria, Grimey will make a cameo appearance in The Simpsons‘ annual Halloween episode, “Treehouse of Horror,” which also happens to be episode 600.

FOX

Since he’s no longer living, he’ll be coming back as an apparition, which is obviously perfect for the Halloween episode. Grimey was mentioned in last year’s “Treehouse of Horror” episode, but this will be the first time he has spoken.

Sideshow Bob and the ghost of Grimey will team up with two other characters over their shared hatred. “They’re forming a sinister squadron of Simpsons enemies to try to kill the Simpsons,” executive producer Al Jean told EW. “If that doesn’t make people tune in, I don’t know what else we can say.”